The inventions described below relate to site-specific delivery of therapeutic agents, structures and catheter systems to achieve site-specific delivery of therapeutic agents, and means for implanting and using these systems to enable delivery of therapeutic agents to the body.
We have been developing catheter systems which enable injection of therapeutic agents into the heart in very precise doses and locations within the heart. The catheter systems use a helical needle, mounted on the distal end of a catheter, to secure the device to the heart wall prior to and during injection. With the helical needle, the injection site can be chosen, mechanically engaged, viewed and confirmed, and maintained for relatively long intraoperative periods or chronically. The helix prevents dislodgment of the needle during injection or during an extended period of injections. Rudimentary mechanisms have been proposed for insertion and rotation of the helix, which must be accomplished from the proximal end of the catheter system. The devices described below provide mechanisms for inserting and driving the drug delivery catheter into the heart, as well as connecting the requisite drug reservoirs to the catheter.
Several embodiments of catheter systems designed to facilitate drug delivery into the heart are described below. The catheter systems include a steerable guide catheter and a drug delivery catheter designed for use together. The drug delivery catheter is inserted through the lumen of the guide catheter, and its handle is dockable within the handle of the guide catheter. Integrated design of the drug delivery catheter with the steerable guide catheter provides for a keyed or matched assembly of the device which provides for limited or controlled extension of the drug delivery catheter tip from the guide catheter tip. In one embodiment, the drug delivery and steerable guide mechanisms are integrated in a single piece handle, and distensible tubing on the proximal end of the drug delivery catheter allows rotation of the drug delivery catheter tube relative to the guide catheter tube and Luer fitting which are in fluid communication with the drug delivery catheter.